The commands "Sandbox/Edit", "Sandbox/Unedit" (indirectly also
"Sandbox/Commit...") are used to flag files in the repository as
being edited (or to un-flag them again). If one user runs a
"Sandbox/Edit" on a file in her sandbox, this is recorded in the
CVS repository. Other users can user the "Sandbox/Editors" command
to retrieve information from the repository regarding who is
currently editing files.

The "Sandbox/Watch" command is used to enable automatic
notification upon "Sandbox/Edit" and "Sandbox/Unedit" commands.
Moreover, "Sandobox/Watch" is used to enable read-only check-outs
of files.

When read-only check-outs are used, the "Sandbox/Edit" command
 in addition to the above  makes the selected files
writable. This way, the read-only status of files reminds you to
"Sandbox/Edit" a file before actually starting to modify it.

Detailes and explanations regarding the Edit and Watch
mechanisms in CVS can be found in the standard CVS documentation:
Cederqvist, section
10.6, "Mechanisms to track who is editing files".

Get Info  Getting a File's
Status

If you want to know which files are edited by whom, the
"Sandbox/Editors" command will retrieve the information from the
server. Command "Sandbox/Watchers" will tell who has registered as
a watcher for a file.

To retrieve all Edit and Watch related information plus general
status information in one go, the "Sandbox/Get Info" command can be
used. It is equivalent to running the commands

"Sandbox/Editors",

"Sandbox/Watchers" and

"Sandbox/Status"

command one after the other.

The information retrieved from the server as described above is
cashed until the the sandbox folder is closed in MacCVSClient.

The Sandbox Inspector Window

In addition to the basic editors and watchers markers in the
flags column of the Sandbox Window (flags E, e, W and w), the
Sandbox Inspector window displays detailed watchers and editors
information.

The Sandbox Inspector window has three panes accessible through
a tabbed interface:

General

Shows file access rights, type and creator codes and the short
(abbreviated) file name of a file that has a name longer than 31
characters.

Editors

Shows detailed editors information.

Watchers

Shows detailed watchers information.

Limitations

The current CVS server implementation supports only one single
sandbox per developer for the Edit and Watch mechanisms. This means
that if you run have two different sandboxes A and B checked out
and run a "Sandbox/Edit" for a file F first in sandbox A and then
for the same file F in sandbox B, the information that you ran a
"Sandbox/Edit" on F in A will be lost once you run a "Sandbox/Edit"
on F in B.

The above restriction is due to the CVS server implementation
(at least up to CVS server versions 1.10) and there is no way
MacCVSClient (or other clients for that matter) can circumvent this
problem.